Gas metering valves such as those manufactured by American Metering Company are in common use in natural gas pipeline operations in which a component of the metering mechanism is a column of liquid mercury, over time, due to seal deterioration or other malfunctions and as the gas pressure fluctuates in the pipeline and through the valve, mercury can be forced out of the valve through otherwise sealed connections, over flow valves and/or relief valves. In standard available meters the mercury thus expelled from the meter spills onto the ground. Spilled mercury has always been a concern and efforts have been made to maintain proper seals and meter functions. In recent years the concern has increased along with increased awareness of the potentially harmful effects of heavy metals, including mercury, on the environment. To the extent that there has been some spillage of mercury from gas metering valves, it has required expensive and time consuming clean up operations. The potential problems associated with clean up operations are particularly acute where the mercury can spill directly onto the soil. The problem also exists, but is not as serious, where the spill may be temporarily trapped on concrete floors or other liquid impermeable surfaces below the gas metering valve.
Periodic seal changes in existing gas meters at regular time intervals are helpful to reduce leakage but cause costly interruption of gas pipeline operations and are not totally effective as the malfunctions cannot always be predicted on the basis of time in service alone. Retrofitting old installations with newer valves would also be costly and newer meters may suffer from the same leakage problems. In many instances retro- fitting would require costly modifications, repairs or even total replacement of the entire installation.
The present invention provides an economical device which is attachable to existing gas meters to thereby collect any mercury which may escape and spill from the valve. The heavy metal is contained until it can be properly removed for recycling or for proper environmentally safe disposal. The containment device is uniquely constructed for rapid and convenient attachment to existing meters without interrupting pipeline operations. It provides a close fitting interface with the existing exposed gas meter surfaces in combination with a close fitting cover to reduce both evaporation of collected and contained mercury and also to reduce collection of rain water and the like atmospheric precipitation.